Network and method for operating the network

A method for operating a network with two industrial programmable logic controllers (PLC) and at least one peripheral device, the method comprising:

• setting in relation to the at least one peripheral device, a first industrial PLC of the two industrial PLCs to an active operating state in which the first industrial PLC sends control instructions to the at least one peripheral device and setting a second industrial PLC of the two industrial PLCs to an idle operating state in which the second industrial PLC is not sending any control instructions to the at least one peripheral device, the two industrial PLCs being directly connected to each other via a synchronization connection which ensures the two industrial PLCs are in the same internal state at all times and always being in different operating states in relation to the at least one peripheral device;
• sending from the first industrial PLC which is in the active operating state in relation to the at least one peripheral device synchronization signals at regular intervals to the second industrial PLC;
• sending from the first industrial PLC activity signals at regular intervals to the at least one peripheral device;
• and
• performing, at the second industrial PLC, which is in the idle operating state in relation to the at least one peripheral device, a check to determine whether the at least one peripheral device has received an activity signal from the first industrial PLC within a predetermined period of time if the second industrial PLC has not received at least one of the synchronization signals within another predetermined period of time from the first industrial PLC and, if the second industrial PLC has not received an activity signal from the first industrial PLC within the predetermined period of time, switching the second industrial PLC from the idle operating state into the active operating state in relation to the at least one peripheral device.